Skip to main content

Full text of "Alaskan glacier studies of the National Geographic Society in the Yakutat Bay, Prince William Sound and lower Copper River regions"

See other formats

As far back as can be seen from Icy Bay the glacier has a moderate slope, suggesting that it comes from a considerable distance. It is possible that its snowfields join those of Nellie Juan and Ultramarine Glaciers, 10 or 12 miles to the north.
There are barren areas around the terminus of Princeton Glacier, which seems also to have had a more expanded stage over a century ago, and to have then coalesced with Chenega Glacier to form the expanded Icy Bay Glacier.
When mapped by Grant and Higgins in 1908 three quarters of the glacier terminus was separated from the water's edge by a low line of morainic or rock hills, but the western margin may have been tidal. Between August 5, 1908, and August 9, 1910, the glacier was wholly inactive, continuing to waste so rapidly that the areas covered by ablation moraine increased decidedly in amount, the ablation moraine of the eastern side practically coalescing with the diagonal medial moraine. By that time, also, there was sufficient retreat of the margin so that it nowhere reached the sea, even the western edge being separated by narrow gravel and sand strips. It is possible that at high tide the water covered this fringe and touched the ice edge in the western part; but there was no terminal cliff, and no icebergs were discharged.
Tiger's Tail Glacier and Smatter Ice Tongues. Tiger's Tail Glacier is a slender ice tongue, extending down over the lip of a hanging valley as a cascading glacier, and reaching the water's edge, so that a few icebergs are probably discharged. It was first mapped by Grant in 1908.
The small ice tongues to the southwest of Tiger's Tail Glacier are fed from adjacent n6v6 fields. One glacier conspicuous from Nassau Fiord terminates in a hanging valley 800 to 900 feet above the sea, to which it sends two streams which flow down either side of a broad mountain spur. The terminus of this glacier is more or less veneered with moraine and in front of it, on the lip of the hanging valley, are good-sized spruces and hemlocks and a thick growth of willow and alder, making it extremely improbable that this glacier could have participated in the expanded condition of 1794 when Chenega, Princeton, and Tiger's Tail Glaciers filled Nassau Fiord. The other ice tongues farther to the southwest terminate high above sea level, several of them in hanging valleys, and from all of them streams with waterfalls descend the fiord wall to the northwestern side of Icy Bay.
Tiger Glacier. Tiger Glacier, at the head of Icy Bay, seen by us only from the mouth of Nassau Fiord, is shown in the map (Fig. 56), photographs, and brief description by Grant and Higgins, to be fed by two good-sized tributaries. It has been mapped for only a little over a mile, although tiie photographs show clearly that it heads some distance farther to the southwest. The adjacent snownelds also feed several small glaciers to the east of it, which terminate several hundred feet above the fiord and supply streams which cascade down the fiord wall. Tiger Glacier, which in the portion seen is severely crevassed, terminates with a steep slope, at the end of which is a vertical cliff less than half a mile wide, from which icebergs are discharged. Near the northern margin bare rock was exposed beneath the terminus of the glacier for over one-third of its width in 1908. A photograph by the Perkins party in 1909 shows that Tiger Glacier had advanced slightly, covering a prominent rock which was visible the year before. There was no marked continuation of this advance up to August 9, 1910.
Retreat of the Icy Bay Glaciers. The first historical suggestion of a glacier in Icy Bay results from the visit of Portlock to Prince William Sound in 1787. In July of that year